


In the Shadows

by Glorious_Monday



Category: Undertale (Video Game)
Genre: Abuse, Alternate Universe - Errortale, Alternate Universe - Underfell, Alternate Universe - Underswap, Alternate Universe of an Alternate Universe, Error Sans - Freeform, Gen, Other Additional Tags to Be Added, Underfell Papyrus, Underfell Papyrus is not nice, Underfell Sans, Underswap Papyrus, Underswap Sans, science sans
Language: English
Status: In-Progress
Published: 2016-02-06
Updated: 2016-02-06
Packaged: 2018-05-18 13:29:14
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 1
Words: 1,026
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5930185
Author URL: https://archiveofourown.org/users/Glorious_Monday/pseuds/Glorious_Monday
Summary: <blockquote class="userstuff">
              <p>When Science Sans makes an unnoticed mistake while messing with different universes, Underswap Sans and Underfell Sans switch universes. The two try their best to find a way to get back to their home, not knowing that someone is watching in the shadows.</p>
            </blockquote>





	In the Shadows

**Author's Note:**

> Whoever guesses who the narrator is gets a cookie

Settle down, settle down. I can't think about anything with all of you talking at once.

This is a story about something that happened quite while ago, but I remember it like it was yesterday. Or was it yesterday? I don't know anymore. Time loses all meaning here. 

It all started when I took a trip to check on a certain scientist. 

He was in his lab, adjusting his glasses as he wrote down notes and observed, wrote down notes and observed, and repeated this. 

I stood in the background of course in the shadows, watching and waiting. For what I wasn't sure. Perhaps the perfect opportunity.

He did this for a while, this constant observing and writing until he stopped for a minute, his eyes scanning his notes up and down like he couldn't believe what he saw in front of him.

"Alphys! I finally got it!", He called out in a moment of excitement and not long after this exclamation the yellow dinosaur came out. Or is she a lizard? I never really knew.

He handed her his notes and she scanned them up and down, a smile forming on her face.

"This is it Sans! This should work perfectly!", She said.  
"Well I have been working down to the bone.", He said and she groaned. It seems to be a classic throughout the universes. Hearing it come from his mouth almost makes me clock him in the face, knocking off his glasses with a bone. I didn't do that though. Things were just getting interesting.

They huddled around a contraption of sorts, punching in numbers and aligning data according to the sheet of paper. 

"This is it.", she says. He nods back to her in mutual agreement.  
"No turning back now."

They both put their hand on a lever and with a silent one, two, three they pulled it down.

A window opened on top of the machine that caught my attention. The window showed Underfell and Underswap, the window flip flopping between the two worlds. It showed the blueberry in his bedroom sitting on his bed and the edgy one sleeping outside in the cold while snow fell down.

The two scientists watched the window, their expressions full of confusion and wonder, taking the sights in.

At the time I thought my vision was getting even worse because for a moment I saw the blueberry in the snow and the edgy one on the bed and then the window disappeared.

There was a moment of silence before the two scientists both grinned.  
"We did it! This proves our theory is correct, there are other universes!", She said happily.  
"Gaster…Gaster would be proud." He says.

I remember something burning inside of me then. That something urging me out of the shadows. It makes you sick, you know? Someone else undeserving using your name, using your friend's name. Not to mention them toying around with the universes. This same something made the strings pop up and go through their souls like soft pudding. What a big surprise I was.

I hopped out of the universe, deciding to clear the rest of it out later. I wanted to check up on Underfell and Underswap just to make sure nothing was out of place. Besides, what great entertainment it would be for the rest of their friends to find their bodies and go crazy finding the killer. Maybe they'll blame the human there I had thought. What great entertainment that would be.

I remember talking to you guys for a bit, answering some of your questions in the middle of the emptiness I call home before I got bored of all of you. You're questions prove to be predictable at times and quite repetitive. 

Anyways, after answering your stupid questions I first went to Underswap. I disliked Underfell the most out of the two.

I hopped in and hid in the farthest corner in the sickly sweet room where the light didn't hit. There he was as part of me had expected, sitting on the racecar bed, confused as to why he was there. 

He looked around the room, at the bookshelf filled with picture books and the drawings and pictures hanged up on the wall. He squinted at one of the pictures with the blueberry and the orange one smiling at the camera. His eyes went wide as if he recognized something.

"Fuck, I'm dreaming again aren't I?", He said as he looked at his hands and then around the room. After a while of waiting he dared to get up and take a step and a step toward the door to the room. He didn't notice me slowly following in the darkness behind.

Then the door opened.  
"Sorry for keeping you waiting Sans, Alphys said she couldn't train with you tomorrow because she and Undy-"  
The orange stopped when he looked up at the skeleton frozen in the middle of the room. 

The said skeleton shut the door quickly and locked the door as he sat down on the floor.

"Fuck, fuck, fuck. This isn't a dream is it? Where am I? Fuck, Boss is going to be so mad if he finds out I'm not at my sentry station.", He says to himself.  
It's amusing, watching a person talk to them self, especially when they were in panic.

The door behind him was banged on from the other side.  
"Hey, open up. Sans is that you?", The voice calls out.

The edgy one stands up, hands on his head as he looks around the room. I stay hidden in the most darkest corner.

How amusing these turn of events turned out to be. Out of all my time jumping into universes I never witnessed a switch before. I knew this would be amusing. Underfell and Underswap were almost opposites, Underfell full of hate and death and Underswap having a 'cute' exterior to you.

I decided to stick around to see this story play out and unfold. If I was lucky maybe it will clear some work for me. I never knew that this change would cause so much trouble in the end.

**Author's Note:**

> I hope you like it so far, I'm new to making fanfiction. Also, Undertale or any of the AUs do not belong to me.


End file.
